1. Field of Invention
The present invention relates to a stereo photographing system including a stereo adapter used for stereo photography and a camera to which the adapter can be detachably fitted.
2. Description of Related Art
According to FIG. 27, a known stereo photographing system principally works as follows. The stereo adapter 12 has a photographing lens 11 attached at the front. The stereo adapter includes the secondary mirrors 13a and 13b which are held at specific angles to the lens axis and primary mirrors 14a and 14b which are placed substantially parallel to the secondary mirrors. The light rays from the subject 15 awe split by the primary 14a, 14b and secondary mirrors 13a, 13b then projected through lens 11 onto a picture frame 16 (film) giving a resultant image of a width d. The images of the picture frame can be observed as a three-dimensional image when split images 15a and 15b are observed by both eyes separately.
When the known stereo adapter (called hereinafter simply the adapter) is attached on a lens-shutter type camera,the finder viewing field mismatches because the photographing area becomes horizontally narrower while the finderviewing field stays the same.
Furthermore, stereo photography with this type of adapter makes vertically long pictures because a pair of images of the same subject are made on the right and left portions of the same picture frame and therefore often gives observers less realistic visual feeling.
With conventional adapters, the camera must be set at a certain lens focal length, the subject must be at certain limited distance, the lens aperture must be stopped down to certain limited opening and must satisfy various other photographing conditions due to the arrangement of the adapter. Because of such limitations, the conventional adapters were not suitable with lens-shutter type cameras equipped with automatic exposure Control, automatic focusing and/or power zoom lenses. Even more importantly conventional adapters can not be applied to fully automatic zoom-lens type cameras. For this reason, there has been no such an adapter available for a lens-shutter type cameras.